1. Field of the Invention
The present invention relates to a screw assembly and more particularly, to a quick positioning screw assembly that can quickly and accurately be installed in a first plate member by a mounting system for securing the first plate member to a second plate member.
2. Description of the Related Art
Fastening plate members in a stack is an application of stacking attachment technique to fully utilize the space. With respect to the functioning of the power drive or speed-adjustment unit of a machine tool, when a machine base failed or an adjustment of the speed of the machine is necessary, a movable plate member will be detachably mounted on a housing of the power drive or speed-adjustment unit. Screw bolts are commonly used to secure the movable plate member to the machine tool. When unfastening screw bolts to dismount the movable plate member from the machine tool, the associating lock nuts may fall from the screw bolts.
FIG. 8 shows a positioning screw assembly for securing two plate members together. As illustrated, the positioning screw assembly is comprised of a cap A, a screw B, a spring member C, a mounting socket D and a Teflon ring F. This positioning screw assembly is to be picked up for installation manually. During installation, hold the cap A with the hand to move the positioning screw assembly into alignment with a mounting through hole E1 on a first plate member E, and then insert the front (bottom) end of the mounting socket D into the mounting through hole E1 to have a mounting flange D1 of the mounting socket D be bonded to the top wall of the first plat member E with a solder paste E2. Picking up the positioning screw assembly for installation manually wastes much time and labor. For automatic installation by a mounting system, the Teflon ring F may be used with the positioning screw assembly. The Teflon ring F is inserted into the bottom hole of the mounting socket D and forced into friction engagement with the periphery of the bottom end of the screw B to lock the cap A, the screw B and the mounting socket D, allowing the positioning screw assembly to be picked up by a mounting system for quick installation. Immediately after bonding of the mounting socket D to the first plate member E, the cap A and the screw B must be rotated to force the Teflon ring F away from the mounting socket D and the first plate member E so that the cap A can be lowered relative to the mounting socket D and the first plate member E for enabling the screw B to be driven into a second plate member E. When many toxic Teflon rings F fall to the ground in the working environment, they will contaminate the surroundings, and the workers' skin may touch the toxic Teflon rings F accidentally. Further, it requires much labor to pick up and pack the fallen Teflon rings F. Further, a special storage place is necessary to keep the packed Teflon rings F in place.